Apnea of prematurity is a significant problem, associated with morbidity and mortality, prolonging hospitalization in newborn intensive care units, and with many late neurological sequellae. Further physiologic understanding of this problem would reduce the costs of this problems in terms of health resources and rehabilitative services needed for this group of high-risk infants. The studies carried out in this laboratory have revealed that sleep state, although an important determinant of respiratory patterns in older patients, does not contribute significantly to apnea in infants; that lung volume plays an important role in breathing patterns, and that maintenance of lung volume may prevent apnea; and that drugs, such as theophylline, used to treat apnea, may have significant overall effects on the organization of sleep-wake cycles in premature infants. In addition, several new methods are under investigation which should permit a deeper understanding of this problem. This includes study of respiratory work and continuous monitoring of oxygen levels in premature infants. BIBLIOGRAPHIC REFERENCES: Ventilatory Response to Carbon Dioxide in Newborn Infants. A.N. Krauss, D.B. Klain, S. Waldman, P.A.M. Auld. Pediatric Research 9:46-50, 1975.